In vitro and clinical evaluations of a dentin bonding system with a dentin primer

The purpose of this study was to investigate the effect of a dentin primer in improving dentin-to-composite bond strengths mediated by a dentin adhesive. The investigation consisted of both an in vitro tensile bond test, in which fresh bovine dentin was used, and clinical evaluation. In the in vitro bond test, bovine dentin surfaces were treated with the primer (an aqueous solution of HEMA) for different durations (10, 20, 30, and 60 seconds) prior to bonding of the light-cured adhesive and placement of a light-cured composite material. For the clinical evaluation, a total of 33 cervical erosion lesions were restored with the combination of the primer, the adhesive, and the composite. To comply with ADA requirements for the acceptance program of dentin-bonding agents, no enamel etching nor any mechanical retentive locks were performed in those restorations. Significant increases in bond strength were obtained in specimens treated with the primer. Regarding the clinical evaluations in which 30 restorations were available for the 6-month recall and 15 restorations were also available for the 1-year recall, all samples demonstrated a retentive rate of 100%.